Is There A Complete Pokedex Action Replay Code For Pokemon Heart Gold?

There certainly is!

Complete pokedex action replay code for Pokemon Heart Gold:

• Before obtain-

94000130 FFFB0000, 62111880 00000000, B2111880 00000000, 000015FC 00010101, 00001560 FFFCC750, 10001564 0000FDFE, 00001308 10001FFF, C0000000 0000000E, 000012CC FFFFFFFF, DC000000 00000004, D2000000 00000000, 94000130 FFFB0000, 62111880 00000000, B2111880 00000000, C0000000 0000000E, 0000130C FFFFFFFF, DC000000 00000004, D2000000 00000000, 94000130 FFFB0000, 62111880 00000000, B2111880 00000000, E0001348 000000A8, 32001FFF 70000000, 00000000 00000000, 08050000 00000000, 00000000 00000000, 00032000 00000000, 02000000 00000000, 08000000 90000000, 00800000 20000000, 00000080 7FFFFFFF, FFFFFFFC FFFCFFFF, 7E7FF9E7 FF9C7EF7, FFFFFFFF FFFFFEFF, F8E3E6FF FFFFFFFF, FEFFFFF7 FF3CFFFF, 081FFFFF DFFFFFFC, FFE7FFFF 39FFDFFF, 00000090 A2AC83FB, E4E4FEFE 03020100, 07060504 0B0A0908, 0F0E0D0C 13121110, 17161514 1B1A1918, D2000000 00000000, 94000130 FFFB0000, 62111880 00000000, B2111880 00000000, C0000000 000001EC, 2000140D 0000003F, DC000000 00000001, D2000000 00000000

• After obtain

94000130 FFFB0000, 62111880 00000000, B2111880 00000000, 000015FC 01010101, 00001560, FFFCC750, 10001564, 0000FDFE, 00001308, 10001FFF, C0000000, 0000000E, 000012CC, FFFFFFFF, DC000000, 00000004, D2000000, 00000000, 94000130, FFFB0000, 62111880, 00000000, B2111880, 00000000, C0000000, 0000000E, 0000130C, FFFFFFFF, DC000000, 00000004, D2000000, 00000000, 94000130, FFFB0000, 62111880, 00000000, B2111880, 00000000, E0001348, 000000A8, 32001FFF, 70000000, 00000000, 00000000, 08050000, 00000000, 00000000, 00000000, 00032000, 00000000, 02000000, 00000000, 08000000, 90000000, 00800000, 20000000, 00000080, 7FFFFFFF, FFFFFFFC, FFFCFFFF, 7E7FF9E7, FF9C7EF7, FFFFFFFF, FFFFFEFF, F8E3E6FF, FFFFFFFF, FEFFFFF7, FF3CFFFF, 081FFFFF, DFFFFFFC, FFE7FFFF, 39FFDFFF, 00000090, A2AC83FB, E4E4FEFE, 03020100, 07060504, 0B0A0908, 0F0E0D0C, 13121110, 17161514, 1B1A1918, D2000000, 00000000, 94000130, FFFB0000, 62111880, 00000000, B2111880, 00000000, C0000000, 000001EC, 2000140D, 0000003F, DC000000, 0000001, D2000000, 00000000

It's rather long, but it should give you a complete pokedex on Pokemon Heart Gold. I hope this is useful!